Papermaking Machine Suction Box with Vibratory Movement having both Longitudinal and Vertical Components

ABSTRACT

Suction boxes located beneath an endless forming wire in a papermaking machine are mounted on resilient supports, and are coupled to vibrators which impart movement to the suction boxes with components in the longitudinal direction of the forming wire and in the vertical direction, and of such resultant direction and amplitude that the suction-boxes at least in their highest position contact the underside of, and move in the same direction as, the forming wire.

ilnite States atet [191 Ekberg 1 Feb. 4, 1975 [54] PAPERMAKING MACHINE SUCTION BOX 1,231,717 7/1917 Davies 162/365 WITH VXBRATORY MOVEMENT HAVING ggi? 3/1318 Dawes 162/365 BOTH LONGITUDINAL AND VERTICAL 4 9 /l 72 Nykopp 162/365 [76] Inventor: Frans Hugo Ekberg,

Angermanlandsgatan 17, 891 00 Ornskoldsvik, Sweden [22] Filed: June 18, 1973 [21] Appl. No.: 370,621

[30] Foreign Application Priority Data July 17, 1972 Sweden 9403/72 [52] U.S. Cl. 162/365 [51] Int. Cl. ..D2lf1/52 [58] Field of Search 162/365, 355, 363

[56] References Cited UNITED STATES PATENTS 789,036 5/1905 Jurgenson 162/365 COMPONENTS Primary Examiner-S Leon Bashore Assistant Examiner-Richard H. Tushin Attorney, Agent, or Firm-Young & Thompson [57] ABSTRACT Suction boxes located beneath an endless forming wire in a papermaking machine are mounted on resilient supports, and are coupled to vibrators which impart movement to the suction boxes with components in the longitudinal direction of the forming wire and in the vertical direction, and of such resultant direction and amplitude that the suction-boxes at least in their highest position contact the underside of, and move in the same direction as, the forming wire.

6 Claims, 3 Drawing Figures PAPERMAKING MACHINE SUCTION BOX WITH VIBRATORY MOVEMENT HAVING BOTH LONGITUDINAL AND VERTICAL COMPONENTS The present invention refers to vibratory equipment for suction-boxes which are used, for example in papermaking machines, for dehydrating fibrous materials, such as wood pulp, which are advanced as an aqueous suspension on an endless screen, such as wire screen, running around front and rear end rolls and supported by a number of intermediate idling supporting rolls.

In the past, it has been proposed to provide papermaking machines with water-removing suction-boxes mounted under the top run ofthe wire screen and capable of oscillating through a small angle in a horizontal plane about a vertical axis through their centre, as in US. Pat. No. 789,036, or capable of oscillating after the fashion of a pendulum through a limited arc in a vertical plane transversely of the longitudinal direction of the wire screen, as in US. Pat. Nos. 1,231,717 and 1,260,878, the purpose of such oscillating movement being to distribute the wear caused by the wire on the top plates of the suction-boxes more evenly. These prior devices have not been concerned, however, with the problem of reducing the drag on the wire screen as it is held on to the top plates of the suction boxes by the vacuum produced in the latter. In paper-making machines such drag may be of a magnitude such that the couch roll which drives the wire screen would be able to overcome the total drag of very few suction-boxes only.

The principal object of the present invention is to bring about a substantial reduction of the drag exerted by a water-removing suction-box in paper-making machines, or similar machines, on the screen moving across said suction-box, and thereby to reduce wear on the screen, on one hand, and on the top plate of the suction-box, on the other hand.

A further object of the invention is to provide for a reduction of the power to be supplied for driving the wire in a paper-making machine having waterremoving suction-boxes across such boxes, and as a result thereof to reduce the risk of rupturing the wire.

Another object of the invention is to make the dehydration of the fibrous suspension on the wire of a paper-making machine more efficient.

Still another important object of the invention is to realize a more even distribution and improved felting of the fibres of stock fed to the wire of, for example, a paper-making machine, and thereby obtain increased strength of a paper or similar web produced from such stock.

The characteristics of the vibratory equipment of the invention by which the abovementioned objects are achieved are that each suction-box is mounted on resilient supports and coupled to vibrators in such a way that it has imparted to it a vibratory movement having a component in the longitudinal direction of the screen and a vertical component, said vibratory movement being adapted in respect of direction and amplitude such that the suction-box, at least in its highest position, contacts the screen with its perforated top plate and moves in the same direction as the screen.

The invention will be described in more detail with reference to the accompanying drawing which, by way of example, diagrammatically illustrates vibratory equipment applied to suction-boxes in a paper-making machine, or the like. In the drawing:

FIG. 1 is a side view of part of a paper-making machine with two suction-boxes and vibratory equipment associated therewith;

FIG. 2 is a top plan view of the same part of the machine; and

FIG. 3 is a vertical section through either of the suction-boxes along the line 3-3 in FIG. 2 on a larger scale.

Referring to the drawing, in FIGS. 1 and 2 there is diagrammatically shown part of a paper-making machine comprising a head box 1 followed by a wire section which comprises a breast roll 2 adjacent the said head box 1, a couch roll 3 at the other end of the wire section and an endless wire screen 4 passing around said rolls. Alternatively, the screen may be made from a plastic or other suitable material. The top run of the wire screen receiving wet stock from the head box 1 is supported in a horizontal plane by a series of idling rolls 5 and by two suction-boxes 6 and 7 placed closely in front of the breast roll 2 and just behind the couch roll 3, respectively. Where needed, additional suction-boxes may be disposed between said boxes 6 and 7. The return run of the wire 4 is passed over carrying, stretch and guide rolls 8 in a well-known way.

As is generally known, the suction-boxes 6 and 7 are each provided with a perforated flat top plate 9, as is more clearly shown in FlG. 3, and are connected to vacuum lines (not shown) through which a vacuum is produced in the interior of the boxes. This top plate 9 may preferable be made from steel, especially acid resistant stainless steel, or from a suitable plastic material or other low friction material.

According to the invention, the suction boxes 6 and 7 are each mounted on resilient cushions 10, for example of rubber, which are placed one at each of the four corners of the boxes on bases 11, so as to be capable of vibration.

At each side of the machine the suction boxes have extensions 12 beyond the lateral edges of the wire screen 4. Fixed on top of said extensions 12 are sloping brackets 13 to each of which is bolted a vibrator 14 of any well-known type capable of producing vibrations in vertical planes in the longitudinal direction of the paper-making machine, i.e. along the wire screen 4. As illustrated more particularly in FIG. 1, the brackets 13 are disposed with their top plane sloping downwards in the travelling direction of the top run of the wire screen 4, which results in the vibrations transmitted to the suction-boxes taking place in a direction as indicated by the double-pointed arrows 15, substantially at right angles to said sloping plane so that the vibratory movement of the boxes will have a horizontal component in the longitudinal direction of the wire screen and another vertical component. It should be noted that where the vibrators 14 are of the unbalanced rotary type the two vibrators of each suction-box are to have opposite directions of rotation so as to neutralize any transverse component of the vibration of the boxes. More particularly, the vibratory movement of the suction-boxes will be of such direction and amplitude that the perforated top plate 9 of the boxes, at least in the highest position of the latter, contacts and moves in the same direction as the wire 4, preferably also applying some force to the underside of the wire to assist in moving it forward. Furthermore, the suction-boxes 6 and 7 are positioned such that the wire 4, when not moving, normally rests on the top plate 9 of the boxes but during operation, as a consequence of the vibratory movement of the boxes, is periodically slightly lifted and at the same time pushed forward by the boxes, while on the other hand the boxes during their return stroke momentarily give up their contact with the wire 4. The frequency of vibration is not critical but may, for example, amount to 1000 to 4000 strokes per minute.

it is to be noted that through the vibration of the suction-boxes 6 and 7 the drag, i.e. the frictional resistance to the movement, of the wire 4 across the top plate 9 will be wholly or partly neutralized not only during the sections of each stroke of vibration when the top plate is out of contact with the wire but also during the rather short section when the top plate with a certain pressure engages the underside of the wire. By this means it is achieved that the driving force necessary for the propulsion of the wire may be reduced and that the life of the wire is considerably increased. Furthermore, as an additional advantage of the vibration of the suctionboxes it is achieved that the dehydration of the fibrous material 16 on the wire becomes more efficient because water drops which tend to hang on to the edges of the perforations of the top plate 9 in spite of the vacuum in the suction-boxes will be shaken off and then readily drawn out through the boxes. Also, an even distribution of the fibres across the whole surface area of the wire and a felting of the fibres is obtained more easily, whereby the wet strength of the finished product is increased.

What I desire to secure by Letters Patent is:

1. Apparatus for dehydrating wet fibrous materials carried on a travelling endless screen, comprising a suction-box having a top plate, resilient means supporting the suction-box under the upper run of said screen with said top plate disposed adjacent the underside of said upper run, and means coupled to the suction-box for imparting vibratory movement thereto having components in the longitudinal direction of said screen and in the vertical direction and of such resultant direction and amplitude that the top plate of the suction-box at least in its highest position contacts the underside of, and moves in the same direction as, said upper run of the screen.

2. Apparatus as claimed in claim 1, in which said top plate is foraminous.

3. Apparatus for dehydrating wet fibrous materials carried on a travelling endless screen, comprising a suction-box havinga top plate, resilient means supporting the suction-box under the upper run of said screen with said top plate disposed adjacent the underside of said upper run, and vibrator means disposed on and coupled to lateral extensions of the suction-box beyond each side of said screen for imparting vibratory movement thereto having components in the longitudinal direction of said screen and in the vertical direction and of such resultant direction and amplitude that the top plate of the suction-box at least in its highest position contacts the underside of, and moves in the same direction as, said upper run of the screen.

4. Apparatus as claimed in claim 3, in which said top plate is foraminous.

5. Apparatus for dehydrating wet fibrous materials carried on a travelling endless screen. comprising a suetion-box having a top plate, resilient means supporting the suction-box under the upper run of said screen with said top plate disposed adjacent the underside of said upper run, bracket means fixed on lateral extensions of the suction-box beyond each side of said screen with top planes'sloping downwards in the travelling direction of the upper run of said screen, and vibrator means mounted on said sloping top planes for imparting vibratory movement thereto having components in the longitudinal direction of said screen and in the vertical direction and of such resultant direction and amplitude that the top plate of the suction-box at least in its highest position contacts the underside of, and moves in the same direction as, said upper run of the screen.

6. Apparatus as claimed in claim 5, in which said top plate is foraminous. 

1. Apparatus for dehydrating wet fibrous materials carried on a travelling endless screen, comprising a suction-box having a top plate, resilient means supporting the suction-box under the upper run of said screen with said top plate disposed adjacent the underside of said upper run, and means coupled to the suction-box for imparting vibratory movement thereto having components in the longitudinal direction of said screen and in the vertical direction and of such resultant direction and amplitude that the top plate of the suction-box at least in its highest position contacts the underside of, and moves in the same direction as, said upper run of the screen.
 2. Apparatus as claimed in claim 1, in which said top plate is foraminous.
 3. Apparatus for dehydrating wet fibrous materials carried on a travelling endless screen, comprising a suction-box having a top plate, resilient means supporting the suction-box under the upper run of said screen with said top plate disposed adjacent the underside of said upper run, and vibrator means disposed on and coupled to lateral extensions of the suction-box beyond each side of said screen for imparting vibratory movement thereto having components in the longitudinal direction of said screen and in the vertical direction and of such resultant direction and amplitude that the top plate of the suction-box at least in its highest position contacts the underside of, and moves in the same direction as, said upper run of the screen.
 4. Apparatus as claimed in claim 3, in which said top plate is foraminous.
 5. Apparatus for dehydrating wet fibrous materials carried on a travelling endless screen, comprising a suction-box having a top plate, resilient means supporting the suction-box under the upper run of said screen with said top plate disposed adjacent the underside of said upper run, bracket means fixed on lateral extensions of the suction-box beyond each side of said screen with top planes sloping downwards in the travelling direction of the upper run of said screen, and vibrator means mounted on said sloping top planes for imparting vibratory movement thereto having components in the longitudinal direction of said screen and in the vertical direction and of such resultant direction and amplitude that the top plate of the suction-box at least in its highest position contacts the underside of, and moves in the same direction as, said upper run of the screen.
 6. Apparatus as claimed in claim 5, in which said top plate is foraminous. 